Discharge device



1960 I E. H. ERMER ,96

DISCHARGE DEVICE Filed May 20, 195'? 1: I is W .5

j I p 3 'r 12 6 9 5 INVENTORL United States Patent 2,963,603 DISCHARGE DEVICE Edmund H. Germer, 10 Marshall St., Apt. 9H, Irvington 11, NJ.

Filed May 20, 1957, Ser. No. 660,207

2 Claims. (Cl. 3123-17) This invention relates to a support of tubular high pressure mercury vapor arc tubes in elongated envelopes. At the present time such are tubes are supported rigidly in metal ferrules as shown for instance in Figure 3 of the Patent No. 2,694,774, this ferrule being mounted on a disc support and this disc support being carried by a ceramic fitting.

According to this patent the arc tube has to have an exact length so as to be able to fill the distance between the disc supports on both ends of the arc tube. An object of my invention is to provide an improved construction so that are tubes with Wide tolerances of their lengths can be used. Furthermore, according to my invention the arc tube is supported elastically in the direction of the axis of the lamp; therefore, breakage of arc tubes during transportation will be reduced. Another important advantage connected with my invention is that the seals can be made longer, with the result that less damage on seals will occur. By using an additional element the arc tube is mounted elastically not only in the direction of the axis of the lamp but also in other directions, for instance in the direction perpendicular to the axis of the lamp; this also is an important step to avoid breakage of the arc tube during transportation of the lamp and, furthermore, helps to cool the end of the arc tube.

According to this invention a helical spring is arranged between the disc support and the end of the arc tube, this spring, respectively its turns, surrounding the seal. The end of the arc tube does not touch the disc support respectively the ferrule, but is resting between two springs within the ferrules on each end of the lamp. The additional element consists of an elastic toroid between the end of the arc tube and ferrule, or any other member replacing this ferrule, as for instance a porous cage or another construction of holder. The principle of my invention consists of using elastic members between the ends of the arc tube and other portions of the lamp, so that the arc tube can elastically move within the lamp in the direction of its axis and/ or other elastic members between ends of the arc tube and other portions of the lamp, so that the arc tube can elastically move within the lamp in other directions than those parallel to the axis of the lamp.

The following description refers to attached drawings showing examples of the invention.

Figures 1 and 2 are cross sectional views of one end of an arc tube assembly and illustrate different embodiments. The numerals represent: 1 the high pressure mercury vapor arc tube (electrodes are not shown) with the seal 2, the end 3 of the lead-in conductor, 4 the support disc mounted in the end fitting of the lamp, 5 the ferrule mounted on the support disc by means of screws 6 and nuts 7, 8 a helical spring resting in a groove of disc 4 and touching a mica disc 9, while 10 an elastic toroid resting in a groove of the ferrule 5 (Fig. 2). 11 is a rod of nickel welded or stranded on wire 12 which is connected with the disc support 4 by means of a nut 13 on one of the screws 6.

Figure 1 shows the arrangement of the arc tube 1 and particularly its end within the ferrule 5. This ferrule (in this case a short metal cylinder) has an inner diameter which is about the same as the outer diameter of the arc tube so that the arc tube can move within the ferrule in the direction of its axis. The length of the spring 8 is originally a little longer than the distance between groove of disc 4 and end of the arc tube. When the arc tube assembly is mounted in the jacket between the end fittings the springs are somewhat pressed together but not too much (the turns should not touch each other) so that after mounting the arc tube can move in both directions. The above mentioned mica ring 9 between spring 8 and end of the arc tube 1 may be useful, but sometimes it is not necessary to use it. The end 3 of the lead-in conductor which may consist of a molybdenum foil, is formed as a loop within which a rod 11 is spot welded. The stranded wire 12 is, according to this example, not tied to the seal (which construction sometimes causes trouble) but, for instance, is formed as a coil and connected with the disc support 4 by means of a nut 13 on one of the screws 6. Of course, it can be connected with the disc 4 in another way also. The figure shows that the end of the arc tube does not sit on the disc as is the case in prior art, but the arc tube end is at a distance from the disc 4 which is equal to about that of the thickness of the disc. The advantages of this construction are: (1) the end is mounted elastically, (2) the length of the arc tube is not critical, (3) the seals can be made longer, (4) the end of the arc tube is better cooled.

In Figure 2 the ferrule (or any other type of holder) 5 has a larger inner diameter than the outer diameter of the arc tube 1 leaving a distance of for instance 5 mm. between arc tube and holder. The ferrule 5 has a groove in which the elastic toroid 10, carrying the arc tube, is resting between arc tube and ferrule, cage, and the like, respectively; the ferrule or cage can have elastic extensions (tongues or the like) supporting the arc tube. The end of the ferrule can be formed as a part of a cone so that it would be easier for the spring 10 to go into the ferrule and to snap into the groove. The principle of my invention consists of using (a) elastic members between ends of the arc tube and portions of the lamp so that the arc tube can elastically move within the lamp in the direction of the axis of the lamp and/or (b) other elastic members between ends of the arc tube and portions of the lamp so that the arc tube can elastically move within the lamp in other directions than'those being parallel to the axis of the lamp. The drawings show that the opening of the disc support is relatively wide while in prior art (see Figure 3 of Patent No. 2,694,774) the holes of such disc supports are not much larger than the diameter of the seal. The drawings show that the hole has a diameter of about 44% of that of the disc support. According to a practical example the disc support has a diameter of 45 mm. and the hole a diameter of 16 mm., that means that the hole has a diameter of 36% of that of the disc support. This improved disc support, of which the diameter of the hole is at least 35% of that of the disc support, can, of course, be used for other constructions of lamps, not only for lamps with the above mentioned springs, but for lamps without springs of the present construction.

Having thus described my invention it is obvious that various modifications and changes can be made without departing from the spirit of my invention, hence I do not wish to be understood as limiting myself to the above description and the attached drawing or the claims.

What I claim is:

1. High pressure mercury vapor lamp comprising a tubular arc tube within an elongated envelope, the envelope on both ends being provided with end fittings, insulating discs supported inside the lamp by the end fittings; arc tube supports being carried' by-the insulating discs, elastic members being placed between the'arctube ends and theinsulating'discs within the arc tube supports.

2. Highpressure mercury vapor lamp comprising a tubular arc tube'within. an elongated envelope, the envelope on both endsbeing provided with end fittings, insulating discs supported inside the lamp by the end fittings, arc tubesupports being carried bythe' insulating discs, elastic membersbeing placed between'the'ends' of the arc tube and the insulating discs within the arc tube supports, said elastic members made in form of a helix.

References Cited in the file of this patent UNITED STATES PATENTS 1,689,485 Hendry Oct. 30, 1928 2,009,203 Pirani July 23, 1935 2,401,555 De Reamer June 4, 1946 2,447,365 Ruesch Aug. 17, 1948 FOREIGN PATENTS 639,190 Great Britain June 21, 1950 

